The present invention relates to a hypodermic syringe, and more particularly to a safety syringe, which is easy to draw the needle back after injection but the needle holder is fixed secured in the barrel when injecting.
A conventional safety syringe, which can draw the needle into the barrel, usually provides the needle holder a little position force for the needle holder is easy to run back into the barrel while an external force is exerted on the needle holder.
There were many inventions to fix the problem as described above, such as provides double locking devices to secure the needle holder. These inventions usually have complex structure and sometime they can not work correctly.
The primary object of the present invention is to provide a safety syringe, which can fixed secure the needle holder in the barrel.
Another objective of the present invention is to provide a safety syringe, which is easy to draw the needle holder into the barrel.
According to the objective of the present invention, a safety syringe comprises a barrel, which has a body, a receiving hole in the body, a front opening at an end of the body and a stop portion in the receiving hole. A needle holder has a hole therein, an elastic lock piece has a claw at distal end, and a dragged portion. The needle holder is to mount a needle. The needle holder is received in the receiving hole of the barrel for the claw can lock with the stop portion in the receiving hole. A supporter, which has a aperture, is slidable received in the hole of the needle holder. And a plunger set has a bumper to move away the supporter and withdraw the needle holder.
For better use, the plunger set may comprises a plunger and a stopper.